Power actuator



Apil 21, 1931. C, s, BRAGG ET AL LSMASB POWER AGTUATOR` Original FiledJan. 5, 1925 ATTORNEY patented pr. 21, 1931 UNTED STATES anni OALEB S.BRAGG, 0F PALM BEACH, FLORIDA, AND VICTOR W. KLIESRATH, OF PORTWASHINGTON, NEW YORK, ASSIGNORS LONG ISLAND CITY, NEW YORK, ACORPORATION OF NEW YORK T0 BRAGGKLIESRATH CORPORATION, OF

POWER ACTUATOR Original application filed January 5, 1925, Serial N'o.506. Divided and this application led August 80,

1926. Serial Our invention consists in the novel features hereinafterdescribed, reference being had to the accompanying drawings whichillustrate several embodiments of the same, selected by us for purposesof illustration, and the said invent-ion is fully disclosed in thefollowing description and claims.

This application is a division of our former application filed January5, 1925, and given Serial No. 506. l

Our invention relates to a power actuator, adapted especially for use inconnection with automotive vehicles propelled by an internal combustionengine, and most conveniently operated by suction from a suction`ypassage of the engine between thethrottle valve and the engine cylinder,or cylinders, as for example, by means of alconnection with the intakemanifold of the engine. In rior application for Letters Patent of thenited States filed December 22, 1923, Serial N o. 682,346, We havedisclosed a` power actuator of this general type connected with theintake manifold of the internal combustion engine by means of a pipe orpassage in which are located an adjustable regulating valve or otherrestricting means, a check valve, and a storage space, or tank, andcomprising a cylinder, a double acting piston therein, and reversingvalve mechanism for applying differential pressures on opposite faces ofthe piston, and said actuator being combined with a foot lever, or otheroperator operated part, and with a brake mechanism or other part to beactuated in such manner that the latter can. be operated by theactuator-under the control of the foot lever while the operator may addhis physical power to the power of the actuator when desired, or in caseof failure of the actuator, may positively operate the actuatedn part byphysical power applied to the foot lever, or other operator operatedpart.

- The regulating valve or other restricting device prevents such largevolumes of air being drawn into the intake manifold as to be likely todilute the explosive charges passing therethrough, so as to stall theengine When idling while the storage space or storage tank provides alarge space in which a partial vacuum or rarification is maintained atall timeskwhile the engine is running, by withdrawing the air therefromin comparatively small quantities, and insures the instantaneousvwithdrawal of the necessary amount of air from the actuator cylinderwhen the reversing valve mechanism is moved to open position, to insurethe instantaneous and effective operation of the actuator.

According yto our invention, we dispense with any extraneous storagespace or storage tank in the suction line extending to the intakemanifold exterior to the actuator cylinder, and maintain a condition ofpartial vacuum or rarication Within the acuator cylinder itself, on bothsides of the piston, which is made to supply the necessary storagespace. Thereby We Vobtain a number of important and advantageous resultsin the construction, installation and operation of the power actuator.Inv the first place, the tank, which is a bulky element, is entirelydone away with and the construction is correspondingly simplified andrendered less expensive. As a partial vacuum is maintained within theactuator cylinder on both sides of the piston therein when the device isin normal or inoperative position, when the reversing valve mechanism ismoved into a position to effect the operation of the actuator, one endof the cylinder'on one side of the piston is connected with the intakemanifold or other vacuum producing means, the other end of the cylinderon the other side of the piston being connected with the atmosphere, andthe immediate result is that the atmospheric air rushed into the end ofthe cylinder to which it is admitted, and effects `the operation of thepiston in the desired direction and to the desired extent without anyappreciable quantity of air being actually withdrawn from the cylinderand admitted to the intake manifold or other suction means, therebyeliminating the drop in the suctionor rarication, which would resultwere the cylinder full of air and this air admitted during theapplication of the brakes. The maximum suction is therefore immediatelyavailable. The restricting valve properly adjusted to prevent stallingthe vmotor While idling would restrict the passage of this air over someeX- tended time, thereby delaying the exertion of the full force of thevacuum, where our present invention is not employed. The air admitted onthe other side of the piston is not being withdrawn until the valvemechanism is reversed and the piston is moved in the opposite direction.This is particularly advantageous in the application of the actuator tothe brake mechanism of automotive vehicles such as automobiles, trucksand motor buses, for example, as when the brake is applied the actuatoris operated without any material admission of air to the intake manifoldand therefore without any possibility of injuriously affecting theexplosive mixture or of stalling the engine, and when the valvemechanism is reversed to efect the release of tle brakes, by operatingthe piston in the opposite direction, the atmospheric air admitted forthe purpose of obtaining the previous application of the brakes can begradually withdrawn to the intake manifold, under the control of theregulating valve, so as to prevent interference with the operation ofthe engine, while securing the effective release of the brake mechanism.lf the motor should stall due to the admission of this air when thebrakes are being released, it would be a matter of far less importancethan the stalling of the motor when the brakes are being applied. It isnot so important that the movement of the piston in a direction torelease the brakes shall be as rapid as the movement of the piston inthe direction to apply the brakes. As a matter of fact, a very slightmovement of the piston in the direction to release the brakes would besufficient to release them, and for this reason continued applicationand releasing of the brakes without allowing the piston to come to theat rest position may be effected with com paratively small amount of airbeing drawn into the intake manifold., and the piston may be permittedto return to itc normal position after an application of the brakes moreslowly than it would be desirable to have it moved in the oppositedirection. Furthermore when the piston comes to the at rest positionafter an application of the brakes, there is a partial vacuum in therear of the cylinder. Therefore, the only air to be exhausted is theamount admitted to the forward end of the cylinder to effect thereleasing ofthe brakes, which is considerably less than the total amountof air that could be contained in the cylinder, were it not for ourinvention, which continually keeps at least one end of our cylinderunder vacuum, the total amount of air in the cylinder would have to beexhausted after each operation of the brakes.

Our invention therefore enables us to simplify and decrease 'the cost ofthe apparatus, and at the same time insures most efficient leonesaoperation of the actuator without prejudice to the continuous andefficient operation of the internal combustion engine from the suctionpassage of which the necessary power or suction for the operation of theactuator is derived.

In our former application above referred to, these features are broadlyclaimed together with one of the specific embodiments for carrying ourinvention into eifect, and the present application is directed toanother specilic embodiment for carrying the invention into elfectdisclosed in our previous application above referred to, but notspecific ally claimed therein, but which is specifically claimed in thisspecication.

Referring to the accompanying drawings,

Fig. l represents a diagrammatic view of an installation in which ourimproved power actuator is connected with the internal combustion engineof an automotive vehicle for the operation of the brake mechanismthereof.

Fig. 2 is an enlarged sectional view illustrating one form of ourimproved actuator embodying our present invention, a portion of thepiston rod and valve actuating sleeve being broken away and showing thepiston in normal retracted position.

Fig. Q- is a detail sectional view of the terminal portions of thepiston rod and valve actuating sleeve omitted from Fig. 2.

ln Fig. l of the accompanying drawings, we have shown diagrammaticallyan installation suitable for use in an automotive vehicle in which oneof our improved actu* ators is shown as interposed in the connectionsbetween a foot lever, 88, and brake mechanism for the vehicle,diagrammati-A ternal combustion engine for propelling the' vehicle, andprovided with an intake manifold, indicated at (il, and communicatingwith the carburetor, Gla, to which is connected a pipe, 62, between thethrottle valve indicated at 61D, and the engine cylinders, in which pipeare located preferably an adjustable regulating valve, or restrictingvalve, 64, a check valve, 65, and a vent valve, 67, normally closed andopening outwardly. The pipe, 62, communicates with one of our improvedpower actuators, the cylinder of which is indicated at 201 in Fig. l,the said pipe having a flexible portion connected to a hollow valveactuating sleeve, indicated at 220, and communicating with the reversingvalve mechanism. The sleeve, 220, is connected by a link, 85, with thefoot lever, 88, which is provided with the usual retracting spring, 89,and the piston rod, 205, of the Leonesa actuator is connected by a link,73, with the brake lever, 72.

In Figs. 2 and 2a, we have shown one form of our improved actuatorembodying our present invention. In this figure, 201 represents theactuator cylinder closed at both ends by heads, 202, connected by boltsindicated at 202a, in Fig. 1, or otherwise. 203 represents the doubleacting piston provided with oppositely disposed gaskets, 204. 205represents a hollow piston rod which extends through `a stufiing box,206, in one end of the cylinder, and is connected at its inner end withthe piston, 203. The hub, 210, of the piston is provided with two valvechambers, 211 and 212 respectively, each of which is provided with twovalve seats preferably conical and coaxial with the axis of the piston.The valve chamber, 211, is provided with seats, 213 and 214, and thevalve chamber, 212, is provided with valve seats, 215 and 216. Thepiston hub is provided with an outlet chamber or suction chamberindicated at 217, which communicates with each of the valve chambersthrough the valve seats, 214 and 215. The piston hub is also providedwith a higher pressure chamber, 218, in this instance communicating 1with the a-tmosphere and with the valve seat, 216, and bv a lateralpassage, 219, with the valve seat, 213. Thevvalve actuating part, inthis instance, a hollow sleeve, 220, passes through a stufhng box, 221,in the cylinder head at,the opposite end of the cylinder from thestuiiino box, 206, the said sleeve extending longitudinally through thepiston hub and valve chambers, and through the hollow pistonrod, 205,and being longitudinally movable to effect the operation of thereversing valves. The valve sleeve may be made convenientlyv in twoparts, 220 and 2205, if desired, and as herein shown in provided with apair of oppositely disposed poppet valves in each valve chamber, thesaid valves being preferably formed of molded rubber and frictionallyengaging the sleeve, so that the sleeve may move through the valve whileforming an air-tight joint therewith. The valves are indicated at 240,241, 242 and 243, the valves 241 and 242 being suction valves, and thevalves, 240 and 243 being air inlet valves. The valves are yieldinglyheld in engagement with their seats, preferably` by a yieldingcushioning device interposed between -the pairs of valves, and indicatedat 250. The actuating sleeve is provided with suitable means for openingone valve of each pair when the sleeve is moved in either direction. Inthis instance, the sleeve is shown provided with a collar, 222, locatedbetween the suction valves, 241 and 242, and adapted to operate eitherof said valves, and the sleeve is also provided with the collars, 231and 232, mounted on the valve sleeve outside of the air inlet valves,240 and 243 respectively, for

plication for Letters-Patent of the United States, filed November 22,1924, and given Serial No. 751,481.

In the form of our invention illustrated in Figs. 2 and 2B, the centralcollar, 222, in the vacuum chamber, 217,. which actuates the suctionvalve, is so located with respect to a stop, in this instance formed bya shoulder, 226% on the fitting, 226, which engages the adjustablefollower, 221", of the stufling box, 221, when the parts are in normalretracted or off position, that when the piston is arrested by theengagement of its nnb with the opposite end of the cylinder, the valveactuating sleeve, 220, will hold the suction valve, 242, slightly oli1its seat, as shown in Fig. 2, thereby placing the cylinder in rear ofthe piston in communication with theuction chamber through a port orports, 235, which connect the valve seat, 215, with that portion of lthecylinder. The other suction calve, 241 being seated, the ports, 234,which connect its valve seat, 214, with the forward portion .of thecylinder are closed. In this instance, we have shown an auxiliarypassage, 242, extending from the valve seat, 215, through the piston tothe forward side thereof, (to the left in Fig. 2). This passage may bemade conveniently by drilling the piston with a drill of small diameter,so that the passage of air therethrough will not be suiiiciently rapidto interfere with the operation of the piston to restore it to retractedor off position (to the right in Fig. 2), when the valve, 242, is openedfor that purpose. This auxiliary passage will, however, permit the `airwithin the cylinder forward of the piston to be exhausted to themanifold during the period when the parts are in retracted or offposition, so that the piston will be submerged in vacuum when linretracted position. Y v

It follows from this construction that as soon as the engine is started,the suction produced in the intake manifold will yexhaust the air fromvthe cylinder of the actuator on both sides of the piston maintaining itsubmerged in vacuum. If now it is desired to apply the brakes, the footlever is actuated to move the sleeve, 220, in the direction of the arrowin Fig. 2, thereby permitting the suction valve, 242, to close, andsubsequently Cit opening the suction valve, 241, and the air inletvalve, 243. This connects the cylinder forward of the piston with thesuction chamber, 217, and admits atmospheric air in rear of the piston,moving the piston forward in a direction to apply the brakes, but noappreciable amount of air will be drawn into the intake manifold throughthe pipe, 62, as the portion of the cylinder forward of the piston isalready exhausted. The forward movement of the piston will follow anyeX- tent of the forward movement of the brake lever, 88, and when themovement of the brake lever stops, the piston will continue to moveforwardly until the air inlet valve, 243, closes, so as to hold thepiston and brakes. lVhere continued applications of the brakes aredesired, a slight release of the foot lever producing a slight rearwardmovement of the valve sleeve will open the suction valve, 242, andconnect both ends of the cylinder with the suction passage, 217,producing a partial or entire equalization of pressures on oppositesides of the piston, which will instantly permit the brakes to relievethemselves, under the action of their retracting means, as spring, 74,slightly retracting the piston. A slight forward movement of the pedallever will again admit air in rear of the piston, and connect thecylinder forward of the piston with the suction chamber, and a numberof' successive applications of the brake can be made without admittingmaterial quantities of air into the intake manifold. W'hen the footlever, 88, is released, the retraeting spring, 89, will move the valve,220, in a direction opposite that indicated by the arrow in Fig. 2, andthe suction valve, 241, will be forced to its seat by the cushioningdevice, and the reversed movement of the sleeve, 220, under the actionof the retracting spring, 89, of the foot lever, will open the suctionvalve, 242, connecting the cylinder in rear of the piston witlrthesuction chamber, and the air inlet valve, 240, will be opened admittingatmospheric air to the Cyliuder forward of the piston through theopening, 283, controlled by said valve, thus returning the piston tonormal retracted position, illustrated in Fig. 2, the piston beingarrested by engagement with the end of the cylinder, and the valveactuating sleeve being arrested by the engagement of the shoulder,22(51, with the follower, 2211. Vhen the parts come to rest, the suctionchamber, 217, will therefore be in communication with the cylinder inrear of the piston by reason of the unseated position of the valve, 242,and will also be connected with the cylinder vforward of the piston b vthe auxiliary passage, 24211, equalizing the pressures on opposite sidesof the piston, and the air previously admitted to effect the reversemovement of the piston, will be exhausted. from the cylinder, producingrarilication on both sides ofthe piston.

The exhaustion of air from the cylinder, therefore, only takes placeduring and after the return stroke of the piston, and the air exhaustedfrom the cylinder is delivered gradually to the intake manifold byproperly regulating the restricting valve, (54, in the pipe, 62, so thatthe operation of the engine will not be interfered with, and theeduction of the air r'nay be retarded as much as desired, as the firstmovement of the piston rearwardly will relieve the pressure of thebrakes, and it is not important that the piston should move rearwardlyas quickly as it moves forwardly to apply the brakes. The withdrawal ofthe air may, therefore, be distributed over a great or less )eriod oftime, according to the `adjustment of the valve, 64, so as to avoid theundue dilution of the eX- plosive charges or the feeding of too small anamount of hydrocarbon fuel, and the piston is left submerged in vacuumand ready for immediate and effective operation to apply the brakes atany moment. As the degree of suction in the suction passages of theengine varies from time to time, we interpose the check valves, G5, inthe pipe, 62, so that after the cylinder is subjected to the great estamount of suction, the condition 0f rariiication so produced willremain, and as the brakes are usually operated at intervals, thegreatest possible rarification will ordinarily exist in the cylinder ofthe actuator at all times, ready to ell'ectively apply the brakes in themanner before described.

We prefer to connect the valve actuating sleeve, 220-220, with thepiston b means providing for a limited amount of iost motion, suiiicientto permit the operation of the valves, so that after this lost motion istaken up, the physical power of the operator can be directly applied tothe piston and the brake mechanism connected therewith, to enable theoperator to add his physical force to that of the actuator, or tooperate the brakes by his physical force alone if the power should failfor any reason, the lost motion permitting the movement of the valves inany case, and serving when power fails to vent the cylinder. In thepresent instance, as shown in Fig. 2, the section, 220, of the valvesleeve is provided with a recessed portion, 220", and a collar, 220, anda piston rod, 205, is in this instance provided with set screws, 205,eX- tending into said recess (or recesses) 220", so that when thesleeveis moved forward by the foot lever to apply the brakes, and the pistonhas followed, applying the brakes to the full capacity of the actuator,the operator may be pushing the foot lever, 88, further forward untilthe rear edge of the recess, 220", engages the screws, 205, apply hisphysical force to the piston and brake mechanism in addition to thepower of the actuator. It also follows from this construction that theoperator, should the power of the actuator fail, may apply the brakesdirectly. The first forward movement of the valve actuating sleeve willset the valvesso as to vent the cylinder forward of the piston, andadmit air in the rear of the piston, to permit this movement. On therelease of the foot lever, the reti-acting spring, 89, will shift thevalve sleeve rearwardly, so as to vent the cylinder (in case of failureof power), and the forward end of the recess, 220D, will engage the sctscrews and move the piston rearwardly to release the brakes and restorethe parts to 0H position. The check valve, 65, shown in Fig. 1, andinterposed in the suction pipe, insures the exhaustion of the cylinderon bot-h sides of the piston to the greatest eXtent permitted at anytime by the operation of the engine by the manipulation of the throttlevalve, while the vent valve, 67a, shown in Fig. l, provides for theventing otthe cylinder should the motor stop, or the suction fail at anytime, and should it become necessary for the operator to apply thebrakes physical power.

What we claim and desire to secure by Letters Patent is 1. In a poweractuator, the combination of a cylinder closed at both ends, a piston insaid cylinder and yielding retracting means operatively connectedtherewith, means for establishing differential pressures on oppositesfaces of said piston including controlling valves located in the piston,an operator operated part, operative connections therefrom to saidcontrolling valves, said piston being provided with a passage forconnecting the portions of the cylinder on opposite sides of the pistoncontrolled by one of said valves for equalizing pressures between theportions of the cylinder on opposite sides of the piston, when saidvalve is in open position.

2. `In a power actuator, the combination of a cylinder closed at bothends, a piston in said cylinder and yielding retracting meansoperatively connected therewith, means for establishing differentialpressures on opposite faces of said piston including controlling valveslocated `in the piston, an operator operated part, operative connectionstherefrom to said controlling valves, said piston A being provided witha passage for connecting the portions of the cylinder on opposite sidesof the piston controlled by one of said valves for equalizing pressuresbetween the portions of the cylinder on opposite sides of the piston,when said valve is in open position, and means for holding the saidvalve in open position when the piston is in retracted position.

3. In a power actuator, the combination of a cylinder closed at bothends, a piston therein and yielding retracting means connectedtherewith, means for establishing differential pressures on opposite`faces of the piston including an air inlet passage, a suction passage,and controlling valve mechanism for the actuator comprising air inletand suction valves for controlling said passages located in the piston,an operator operated part, connections therefrom to said valves, saidactuator being provided with a passage in the piston controlled by asuction valve of said controlling valve mechanism, for connectingportions of the cylinder on opposite sides of the piston with each otherand with said suction passage, when the said controlling suction valveis in open position.

4:. In a power actuator, the combination of a cylinder closed at bothends, a piston therein and yielding retracting means connectedtherewith, means for establishing differential pressures on oppositefaces of the piston including an air inlet passage, a suction passage,and controlling valve machanism for the actuator comprising air inletand suction valves for controlling said passages located in the piston,an op-erator operated part, connections therefrom to said valves, saidactuator being provided with a passage in the piston controlled by asuction valve of said controlling valve mechanism, for connectingportions of the cylinder on opposite sides of the piston with each otherand with said suction passage, when the said controlling suction valveis in open position, and means for maintaining the said controllingsuction valve in open position when the piston is in retracted position,to maintain' the piston submerged in vacuum.

5. ln a power actuator, the combination of a cylinder closed at bothends, a piston in said cylinder and yielding retracting meansoperatively connected therewith, means for establishing differentialpressures on opposite faces of the piston including an air inletpassage, a suction passage, and controlling valve mechanism for` theactuator comprising suction and air inlet valves controlling saidpassages, and provided with valve seats, an operator operated part,comiections therefrom to said controlling valve mechanism, said pistonbeing provided with an auxiliary passage therethrough, terminating atone end in a valve seat for a suction valve of said controlling valvemechanism, for connecting the portions of the cylinder on opposite sidesof the piston with each other and with the suction passage, when thesaid valve is in open position.

6. ln a power actuator, the combination of a cylinder closed at bothends, a piston in said cylinder and yielding retracting meansoperatively connected therewith, means for establishing differentialpressures on opposite faces of the piston including an air inletpassage, a suction passage, and controlling valve mechanism for theactuator com rising suction and air inlet valves controiling saidpassages, and provided with valve seats,

an operator operated part, connections therefrom to said controllingvalve mechanism, said piston being provided with an auxiliary passagetherethrough, terminating at one end in a valve seat for a suction valveof said controlling valve mechanism, for connecting the ortions of thecylinder on opposite sides of t e piston with each other and with thesuction passage, when the said valve is in open position, and means formaintaining said suction valve in open position when the piston is inretracted position, to maintain the piston submerged in vacuum.

:17. In a power actuator, the combination with a cylinder, closed atboth ends, a. double acting piston v insaid cylinder and yieldingretracting means operatively connected therewith, a reversing valvemechanism including'a'vacuum chamber and suction passages extendingtherefrom to the cylinder on both sides of the piston, an air inletpassage, and passages for connecting it with the cylinder on both sidesor the piston, and valves for controlling said'suction and air inletpassages, a vacuum producing means connected with said vacuum chamber,means tor holding one of said suction valves unseated when the piston isin retracted position, the piston being provided With a passageltherethrou h, for connecting the portions of the cylin er on oppositesides of the piston, said passage beingmaintained in open conditionWhile said suction valve is unseatedn 8. In a power actuator', thecombination with a cylinder closed both ends, a double acting piston insaid cylinder yielding retracting means operatively connected therewith,a reversing valve mechanism including a vacuum chamber and suction passages extending therefrom to the cylinder on both sides of the piston,an air inlet passage, and passages for connecting said inlet passagewith the cylinder on both sides of the piston, and valves forcontrolling said suction and air inlet passages, a vacuum producingmeans connected with said vacuum i chamber, said piston being providedwith an sage with the cylinder both s..

auxiliary passage therethrough, terminating at one end in the seat forthe suction valve controlling the connecting passage to the portion ofthe cylinder in rear of the piston, for connectin the portions ci thecylinder on opposite sides of the piston with each other end with thesuction passage, when the said suction valve is in open position.

9. In a power actuator, the combination with a cylinder closed at bothends, a. double acting piston in said cylinder and yieldinfr retraetingmeans operatively connected therewith, areversing valve mechanismincluding a vacuum chamber and suction passages extending therefrom tothe cylinder on both sides ol the piston, an air inlet passage, andpassages for connecting said inlet pasrcs the piston, and valves forcontrolling said suction and air inlet passages, a vacuum producingmeans connected With said vacuum chamber, said piston being providedwith' an auxiliary passa e therethrough, terminating at one end in Vt ieseat for the suction valve controlling the connecting passage to theportion of the cylinder in rear of the piston, for connectingthe'portions of the cylinder on opposite sides of the piston with eachother and with the suction passage, by the opening of said suctionvalve, and means for holding the said suction. valve unseated Whenthepiston is in retracted position, to maintain the piston subnier ed invacuum.

10. In a power actuator, t e combination of a cylinder closed at bothends, a piston therein and yielding retracting means operativelyconnected therewith, reversing valve mechanism located in the piston andincluding an outlet chamber, passages connecting said chamber' With thecylinder on both sides of the piston, an inlet chamber for higherpressure fluid, passages connecting said inlet chambery With thecylinder on both sides of the piston, outlet and inlet valvescontrolling said passages, yielding means for normally holding all ofsaid valves seated, said piston being provided with an auxiliary passagecontrolled by one of said outlet valves for connecting ortions of thecylinder on opposite sides oiD the piston with each other and with saidout-let chamber, when the said outlet valve is in open position, anoperator operated part connected operatively with said inlet and outletvalves, and means i'or holding the outlet valve controlling saidauxiliary passage in open position when the piston is in retractedposition.

l1. In a power actuator, the combination of a cylinder closed at bothends, a piston therein and yielding retracting means operativelyconnected therewith, reversing valve mechanism located in the piston andincluding an outlet chamber, passages connecting said chamber with thecylinder on both sides of the piston, an inlet chamber for higherpressure fluid, passages connecting said inlet chamber with the cylinderon both sides oi?` the piston, outlet and inlet valves controlling saidpassages, yielding means for normally holding all of said valves seated,said piston being provided with an auxiliary passage controlled by oneof said outlet valves for connecting portions of the cylinder onopposite sides of the piston with each other and With said outletchamber, when the said outlet valve is in open position, a valveoperating part provided with means for operatively engaging said outletand inlet valves, means for arresting said valve operating part inposition to hold the outlet valve controlling said auxiliary' passage inopen position when the piston is in retracted poaeoaaes both sides ofthe piston, suction and inlet,

valves controlling said passages, and yielding means normally tending toseat said valves, said piston being provided with an auxiliary passagetherethrough controlled by one of said suction valves for connectingportions of the cylinder on opposite sides of the piston with each otherand with said suction passa-ge, of a suction pipe connecting the suctionchamber with the suction passage of the engine, means for connecting theactuator pistonavith a part to be operated, yielding retracting meansfor said piston and part to be operated, and an operator operated partoperatively connected with said suction and inlet valves.

13. ln an automotive vehicle provided with an internal combustion enginehaving a suction passage, the combination with a power actuatorcomprising among itsmembers a. cylinder closed at bothends, a pistontherein, reversing valve mechanism located in the piston, including asuction chamber, passages connecting it With the cylinder on both sidesof the piston, an air inlet chamber, passages connecting it with thecylinder on both sides of the piston, suction and inlet valvescontrolling said passages, and yielding means normally tending to seatsaid valves, said piston being provided with an auxiliary passagetherethrough controlled by one of said suction valves for connectingportions of the cylinder on opposite sides of the piston with each otherand With said suction passage, of a. suction pipe connecting the suctionchamber with the suction passage of the engine, an operator operatedpart connected with said inlet and suction valves, means for holding thesuction valve controlling said auxiliary passage in open position whenthe piston is in retracted position, means for connecting the actuatorpiston with a part to be actuated and yielding means for retracting saidpiston and part to be actuated.

14. In an automotive vehicle provided with an internal combustion enginehaving a suction passage, the combination with a power actuatorcomprising among its menibers a cylinder closed at both ends, a pistontherein, reversing valve mechanism located in the piston, including asuction chamber, passages connecting it with the cylinder on both sidesof the piston, an air inlet chamber, passages connecting it with thecylinder on both sides of the piston, suction and inlet valvescontrolling said passages, and yielding means normally tendine to seatsaid valves, said piston being provided with an auxiliary passagetherethrough controlled by one of said suction valves for connectingportions of the cylinder on opposite sides of the piston with each otherand with said suction passage, of a suction pipe connecting the suctionchamber With the suction passage of the engine, a valve actuating partextend ing through the inlet and suction valves and provided with meansfor operatively engaging them to open one inlet valve and one suctionvalve When moved in either direction,

'an operator operated part connected With the valve actuating part,means for arresting the valve controlling said auxiliary passage in openposition when the piston is in retracted position, means for Yconnectingsaid piston with a part to bc actuated, and yielding means forretracting the part to be actuated and said piston.

15. ln an automotive vehicle provided with an internal combustionengine, having a suction passage, and brake mechanism for the vehicle,the combination with a power actuator comprising `among its members acylinder closed at both ends, a double acting piston in said cylinder,reversing valve mechanism located in said piston and including a suctionchamber, passages connecting it with the cylinder on both sides of thepiston, air inlet passages communicating with the cylinder on both sidesof the piston, suction and air inlet valves controlling said passages,yielding means normally tending to seat said valves, said piston beingprovided With an auxiliary passage extending therethrough, terminatingat one end in the valve seat for one of the suction valves, and adaptedto connect the` portion of the cylinder on both sides of the piston witheach other and with the suction chamber when said suction valve isunseated, of a suction pipe for connecting said suction chamber with thesuction passage of the engine, a valve actuating part extending throughsaid valve and to the exterior of the cylinder, and provided with meansyfor engaging said valves to open one inlet and one suction valve Whenmoved in either direction with respect tothe piston, an operatoroperated part connected With the valve actuating part, means forconnecting the piston with the brake mechanism of the vehicle, yieldingmeans for retracting the brake mechanism and piston, and means forarresting the valves actuating part in position to hold unscated thesuction valve controlling said auxiliary passage When the piston is inretracted position.

16. ln an automotive vehicle provided with an internal combustionengine, having a suction, passage and brake mechanism 'for the vehicle,the combination ivith a power actuator comprising among its members acylinder clbsed at both ends, a double acting piston in said cylinder,reversing valve mechanism located in the piston and including a suctionchamber, passages connecting it with the cylinder on both sides of thepiston, air inlet passages for the cylinder, and suction and air inletvalves controlling said passages, yielding means normally tending 'toseat said valves, a valve actuating part movable with and with respectto the piston, an operator operated part connected with the valveactuating part, said valve mechanism being constructed so thata/movement ot the valve actuating part in cithei1 direction with respectto the piston will eliect an actuation of the piston in the samedirection, said piston being provided With an auxiliary passageextending therethrough and controlled by one of said suction valves, andadapted to connect the portions of the cylinder on both sides of thepiston with each other and with the suction chamber when the suctionvalve is unseated, said suction chamber being connected with the suctionpassage ot the engine, means for connecting the piston with the brakemechanism of the vehicle, yielding means for retracting thebraleniechanisin and piston, means for arresting the valve actuatingpart in position to hold unseated the suction valve controlling saidauxiliary passage when the piston is in retracted. position, and meansfor connecting the operator operated part with said bralre .inechanism,to enable the operator to apply his physical 'force thereto, in additionto that o the actuator.

or in case of failure ot power.

l?. In an automotive vehicle provided with an internal combustionengine, having a suction passage and bralte mechanism for the vehicle,the combination with power actuator comprising among its members acylinder closed at both ends., a double acting piston in said cylinder,reversing valve mechanism located in the piston and includinga suctionchamber, passages connecting it with the cylinder' on both sides of thepiston, air inlet passages for the cylinder, and suction and air inletvalves controlling said passages, yielding means normally 'tending toseat said valves, a valve actuating part movable. with and "with respecttc lie piston, an operator operated part connected with the valveactuating part, said valve mechanism being constructed so that a, vementot the valve actuating part in either direction with. respect to thepiston will actuation of the piston in the saine direction, said pistonbeing provided ivith c" nuiriliary passage extending therethrou indcontrolled by one ot said suction. vaives, nd ,dapted t connect theportions oi the sides et the piston with the suction chamber when thesuction valve is unseated, said suction chamber being connected with thesuction passage of the engine, means for connecting the piston with thebrake mechanism oi the vehicle, yielding means for retracting the brakemechanism and piston, means for arresting the valve actuating part inposition to hold unseated the suction valve controlling said auxiliarypassage ivhen the piston is in retracted position, and means forlimiting the relative Inovement between the valve actuating part and thepiston, to enable the operator to apply his physical force to the brakemechanism in addition to that ot the actuator, or in (iase ot failure ofpower.

18. ln an automotive vehicle provided with an internal combustionengine, having a suction passage and brake mechanism for the vehicle,the combination with a power actuator comprising among its members acylinder closed at both ends, a double acting piffton in said cylinder,reversing valve mechanism located in the piston-and including a suctionchamber, passages connecting it with the cylinder on both sides ot thepiston, air inlet passages for the cylinder, and suction and air inletvalves controlling said passages, yieldingj means normally tending toseat said valves, a valve actuating part movable With and with respectto the piston, an operator operated part connected With the valveactuating part, said valve mechanism being constructed so that amovement ot the valve actuating part in either direction with respect tothe piston will effect an actuation ot the piston in the sainedirection, said piston being provided with an auxiliary passage ei:-tending therethrough and controlled by one ot said suction valves, andadapted to connect the portions of the cylinder on both sides ot' thepiston with each other and with the suction chamber `when the suctionvalve is unseated, said suction chamber being connected with the suctionpassage ot the engine, means for connecting i the piston With the bralremechanism ot the vehicle, yielding means for retracting the brakemechanism and piston, said operator operated part ybeing connected withthe piston by means providing lost motion, to enable the operator to addhis physical 'torce to the brale mechanism in addition to that of theactuator, or in case of failure of poWer 19. In a power actuator, thecombination of a cylinder closed both ends, a piston in said cylinder,and yielding retracting means therefor, means for establishingditerential pressures on opposite faces of said piston includingcontrolling valves located in the piston, an operator operated part,operative connections theretrom to said controlling valves, said'pistonbeing provided with a passage for connecting the portions ot thecylinder on opposite sides ot the piston controlled by one of saidvalvesfor e ualizin pressures between the portions o the cy inder on oppositesides of the p1s ton, when said valve is in open position, said operatoro erated part being connected with the piston y means providing lostmotion, to enable the operator to apply his physical force to the partto be operated by said piston in addition to the power of the actuator,or in case of failure of power.

20. In a power actuator, the combination of a cylinder closed at bothends, a piston in said cylinder, and yielding retractin means therefor,means for establishing di erential pressures on opposite faces of saidpiston including Vcontrolling valves located in the piston, an operatoroperated part, operative connections therefrom to said controllingvalves, said pistons being provided with a passage for connecting theportions of tlze cylinder on opposite sides of the piston controlled byone of said'valves for equalizing pressures between the ortions of thecylinder on opposite sides o the iston,when said valve is -1n openposition, an means for holding thev said valve in open sition when thepiston is in retracted pos1tion,.to maintain the piston submerged invacuum, said operator operated part being connected with the piston Ebymeans permitting lost motion, to enable the operator to a ply hisphysical force to the part operate by the piston in addition to thepower of the actuator, or in case of failure of power.

21. In an actuator, a cylinder,'a piston movable therein, passages forconveying high and low pressure motive Huid to and from' said cylinderto actuate said piston, relatively movable valves for said passages, anoperator operated part for controlling said valves and an auxiliarypassage connecting both ends of said cylinder with said low pressure andcontrolled by one of said valves. i

22. In an actuator, a cylinder, a piston movable therein, inlet andoutlet' passages lfor conveying motive iiuid to and from said cylinderto actuate said piston, relatively movable inlet and outlet valvesfor'said passages, an operator operated part for controlling said valvesand an auxiliary passage connecting theportions ofthe cylinder onopposite sides of the piston with each otherl and with the outletpassage, and independently controlled by one of said outlet valves. f

23. In an actuator, a cylinder, a piston movable therein, inlet andoutlet passages' for conveying motive fluid to and from said cylinder toactuate said piston, relatively movable inlet and outlet valves for saidpassages, an operator operated part for controlling said valves, anauxiliary passage connecting the outlet passages and both ends of thecylinder andy controlled by one of said outlet valves, and means actingto unseat saidout'let valve adapted to equalize pressures on both sidesthereof and controlled by one of said valves.

25. In an actuator, a cylinder, a piston movable therein, passages forconveying motive fluid to and from said cylinder to actuate said piston,valves for said passages, an operator f operated part, for controllingsaid valves, an auxiliary passage through said piston adapted toequalize pressures on both sides thereof and controlled by oneA of saidvalves, and means acting to unseat the valve controlling the auxiliarypassage when said piston is in its normal retracted position.

26. In combination, an automotive vehicle having a power plant capableof driving the same and producing a source lof low pressure, a part tobe actuated, an actuator for said part including a cylinder and-a pistonmovable therein, passages for connecting said cylinder with said sourceof low pressure from the power plant, and a source of high pressure toactuate the piston, relatively movable valves for controlling saidpassages, an operator operated part for controlling said valves, and anauxiliary passage connecting both ends of said cylinder for equalizingpressures on opposite sides of the piston, said auxiliary passage beingcontrolled by a low pressure valve independent of other valves.

27. The combination with an automative vehicle having a power plantcapable of driving the same and producing a source of lowpressure, of apart to be actuated, an actuator :for said part including a cylinder anda piston movable therein, passages for connectlng said cylinder withsaid low pressure source, and a source of high pressure, relativelymovable valves for controlling said passages, an operator o rated partfor controlling said valves, an an auxiliary passage connecting bothends of the cylinder to equalize pressure on opposite sides of thepiston, said auxiliary passage being controlled by one of said valvesindependent of other valves.

28. The combination with an automotive .valves for controllmg saidpassages, an operator operated part for controlling said valves, anauxiliary passage connecting both ends of the cylinder to equalizepressure on opposite sides of the piston,said auxiliary passage beingcontrolled by one of said valves,

and means acting to unseat said valve inde-- pendent of other valveswhen the piston is in normal retracted position.

29. In combination, an automotive vehicle having a power plant capableof driving the same and producing a source of low pressure, a part to beactuated, and an actuator for said part including a cylinder and apiston movable therein, passages for connecting the cylinder with saidsource of low pressure and with a source of high pressure to actuatesaid piston operator actuated valves for controlling said passages, andan auxiliary passage 4extending through the piston for connectmg bothends of the cylinder with each other and with the source of lowpressure, said auxiliary passage being controlled by one of said valves.

30. In combination, an automotive vehicle having a power plant capableof driving the same and producing a source of low pressure, a part to beactuated, and an actuator for said part including a cylinder and apiston movable therein, passages for connecting the cylinder with saidsource of low pressure and with a source of high pressure to actuatesaid piston operator actuated valves for controlling said passa es, anauxiliary passage eX- tending throng the piston for connecting both endsof the cylinder with each other and with the source of low pressure,said auxiliary passage being controlled by one of said controllingvalves, and means acting to unseat said controlling valve when thepiston is in normal retracted position to connect the portions of thecylinder on opposite sides of the piston with each other and with thesource of ow pressure.

In testimony whereof we afx our signatures.

CALEB S. BRGG. VCTR "W

